4 Answers
4

It is for adjusting the suspension on a medium to high-end mountain bike (fork), hence the lack of 'Presta' option.

Since you will be returning it, to keep the shop happy and get what you really need, consider getting:

A track pump with gauge and aluminium body. Look for one with a well
engineered head that does Presta and Shrader valves. The easiest
ones to use have a lever that you fold out to get a snug fit.

For the road, carry an affordable, light mini-pump with as few
movable parts as possible. The deluxe mini-pumps with dual-action,
fancy gauges and other features have a tendency to rattle apart,
rendering them useless when you need it.

Keep it simple is what you want with a mini-pump, it only has to get you home and you hopefully will have a proper track pump with gauge at home.